If you’re confused about the difference between “it’s” and “its”, or unsure how to spell “cemetery”, you’re not alone, and there’s plenty of evidence to prove it.

That’s the conclusion of two young Americans who took it upon themselves to correct public typos during a three-month road trip across the country. They have written about the trip in a book that exposes deficits in both public education and attention to detail.

“The Great Typo Hunt” describes a nationwide mission by Jeff Deck and Benjamin D. Herson, both 30, to rid America of signs that add an extra “n” to “dining”, or insist that “shipping” is spelled with one “p”.

Deck, a magazine editor, and Herson, a bookseller, drove across the country in the spring of 2008 armed with sharpies, pens and whiteout, correcting spelling, removing surplus apostrophes and untangling subject-verb disagreement on signs outside stores, gas stations, parks and public buildings.

Calling themselves the Typo Eradication Advancement League, they found hundreds of signs indicating the writers either didn’t know or didn’t care that their spelling, grammar, or punctuation was wrong, and were apparently unaware that their mistakes risked exposing them to public derision or, worse, misunderstanding.

In Atlanta, they found a sign advertising both a “pregnacy” test and a “souviner” of the city to remind tourists of their visit…